Cornette J, Laker S, Jeffery B, Lombaard H, Alberts A, Rizopoulos D, Roos-Hesselink JW, Pattinson RC Validation of maternal cardiac output assessed by transthoracic echocardiography against pulmonary artery catheterization in severely ill pregnant women: prospective comparative study and systematic review. Ultrasound Obstet Gynecol. 2017 Jan;49(1):25-31. doi: 10.1002/uog.16015. Epub 2016 Nov 28. Review.
Critchley LA, Critchley JA A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput. 1999 Feb;15(2):85-91.
Dyer RA, James MF Maternal hemodynamic monitoring in obstetric anesthesia. Anesthesiology. 2008 Nov;109(5):765-7. doi: 10.1097/ALN.0b013e31818a3825. Review.
Easterling TR, Watts DH, Schmucker BC, Benedetti TJ Measurement of cardiac output during pregnancy: validation of Doppler technique and clinical observations in preeclampsia. Obstet Gynecol. 1987 Jun;69(6):845-50.
Engoren M, Barbee D Comparison of cardiac output determined by bioimpedance, thermodilution, and the Fick method. Am J Crit Care. 2005 Jan;14(1):40-5.
Hunter S, Robson SC Adaptation of the maternal heart in pregnancy. Br Heart J. 1992 Dec;68(6):540-3. Review.
Keren H, Burkhoff D, Squara P Evaluation of a noninvasive continuous cardiac output monitoring system based on thoracic bioreactance. Am J Physiol Heart Circ Physiol. 2007 Jul;293(1):H583-9. Epub 2007 Mar 23.
Lee W, Rokey R, Cotton DB Noninvasive maternal stroke volume and cardiac output determinations by pulsed Doppler echocardiography. Am J Obstet Gynecol. 1988 Mar;158(3 Pt 1):505-10.
Ohashi Y, Ibrahim H, Furtado L, Kingdom J, Carvalho JC Non-invasive hemodynamic assessment of non-pregnant, healthy pregnant and preeclamptic women using bioreactance. [corrected]. Rev Bras Anestesiol. 2010 Nov-Dec;60(6):603-13, 335-40. doi: 10.1016/S0034-7094(10)70075-1. English, Portuguese, Spanish. Erratum in: Rev Bras Anestesiol. 2011 Jul-Aug;61(4):IX.
Roberts LA, Ling HZ, Poon LC, Nicolaides KH, Kametas NA Maternal hemodynamics, fetal biometry and Doppler indices in pregnancies followed up for suspected fetal growth restriction. Ultrasound Obstet Gynecol. 2018 Oct;52(4):507-514. doi: 10.1002/uog.19067.
Vinayagam D, Bowe S, Sheehan E, Thilaganathan B, Khalil A Non-Invasive Haemodynamic Monitoring in Pregnancy: A Comparative Study Using Ultrasound and Bioreactance. Fetal Diagn Ther. 2017;41(4):273-282. doi: 10.1159/000446650. Epub 2016 Oct 6.
Vinayagam D, Patey O, Thilaganathan B, Khalil A Cardiac output assessment in pregnancy: comparison of two automated monitors with echocardiography. Ultrasound Obstet Gynecol. 2017 Jan;49(1):32-38. doi: 10.1002/uog.15915.
Validation of a Non-invasive Cardiac Output Monitor (NICOM) in Pregnant Women With Structural Heart Disease
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
